Studies on Dielectric and a.c. Conductivity Behavior of Activated Carbon-Filled Epoxy-Graded Composites

In this study, an activated carbon-filled epoxy resin gradient composite was developed. The dielectric constant increased gradually with the increase of activated carbon content in the direction of centrifugal force, due to gradual increase in carbon concentration. Dielectric constant and a.c. conductivity increased with increase in temperature. Increase of a.c. conductivity with temperature was due to the formation of the polycondensed rings, which allowed charge transport in the composite. By using the power law sigma a.c.=As, values of constant A and frequency exponent s were calculated. It has been found that a decrease from sample 1 to 4 due to the increased concentration of activated carbon in the composite. Small values of activation energy obtained at higher frequencies suggest that the conduction in the composite is mainly due to hopping of charge carriers.